For port crane facilities and the like including a movable body such as a trolley that hoists a container and traverses, techniques are known that, in order to avoid a collision between a container or a container-grabber that is lowering or traversing while being hung from the movable body and an object that is liable to come into contact with the container or the container-grabber, achieve low-impact landing, or prevent a collapse of stacked containers due to the container or the container-grabber transversely hitting the object, detect the position of the object via a sensor and automatically decrease the velocity of the lowering or the traversing.
Japanese Patent Laid-Open No. 2005-104665 discloses a container collision prevention system in which a two-dimensional laser sensor having a sectorial detection range in a traverse movement direction is attached to a part of a movable body, the part capable of ensuring a view of a lower edge portion of a container hoisted with a container-grabber, the sensor performs scanning in the traverse movement direction, and control means for controlling a position to which the container is moved, based on data on a position of the lower edge portion of the hoisted container and data on a position of an upper edge of placed containers is provided.